A bearing system, using which the propeller blades of an aircraft propeller are adjustably mounted on a hub, is known, for example, from DE 10 2004 060 022 A1. The bearing system is constructed from a primary adjustable bearing and a secondary adjustable bearing, which are each designed as ball bearings and are components of a pre-assembled unit. A lubricant is largely stored in the bearing system and is kept within a specific volume, inter alia, by lubricating oil surge rings, which enclose bearing rings.
A device for propeller blade adjustment, which includes a rolling bearing arrangement having balls and rollers as rolling elements, is known, for example, from GB 2 244 525 A. A pre-tensioning force is applied in this case between a first row of rolling elements, which is formed from balls, and a second row of rolling elements, which is formed from rollers. Corresponding to the bearing system known from DE 10 2004 060 022 A1, an adjustable propeller blade is also connected to inner rings of the bearing in this case, while the associated outer rings are located on the hub.
The adjustability of propeller blades is required in particular in propfan engines. An example of a jacketed propfan engine having adjustable blades is disclosed in DE 38 18 466 C1. In contrast, US 2012/0134822 A1 describes a non-jacketed propfan engine.
Propfan engines are aircraft engines, which have a particularly high bypass ratio to increase the efficiency in relation to older engine versions. In this case, a higher air throughput is generated by the propeller blades, which, as is known from the cited prior art, may either be located inside a jacket or outside any type of housing. To adapt the engine output to the present flight situation at a preferably constant rotational speed of the propulsion engine, the attack angle of the propeller blades is adjusted by pivoting about their axis. For this purpose, each propeller blade is pivotably connected to the hub of the propeller with the aid of a rolling bearing.